Wire wound disc armature

ABSTRACT

A wire wound motor armature constructed by forming successive groups of single turn armature coils, the coils within each group being in registry with one another, the groups being indexed relative to one another, and all coils being interconnected in a wave configuration.

United States Patent Raymond J. Keogh Huntington, N.Y.

Nov. 10, 1969 Apr. 20, 1971 Photocircuits Corporation Glen Cove, N.Y.

Continuation of application Ser. No. 620,306, Mar. 3, 1967, now abandoned.

I 72] Inventor [21 Appl. No. 22] Filed [45] Patented [73] Assignee [54] WIRE WOUND DISC ARMATURE 10 Claims, 7 Drawing Figs.

[52] U.S.Cl 310/268 [51] Int.Cl H02k 1/22 [50] Field ofSearch 310/268, 207, 268 (Foreign) [56] References Cited UNITED STATES PATENTS 229,191 6/1880 Seeley 310/268 Primary Examiner-Milton O. I-Iirshfield Assistant Examiner-Mark O. Budd Attorney-Morgan, Finnegan, Durham and Pine ABSTRACT: A wire wound motor armature constructed by forming successive groups of single turn armature coils, the coils within each group being in registry with one another, the groups being indexed relative to one another, and all coils being interconnected in a wave configuration.

PATENTEn'APnzolsn SHEET 1 BF 4 INVENTOR. RAYMOND J: KEOGH PATENTEDAPRZOIBYI 3.675.624

sum 2 0F 4 lib 0 o 0 RAYMOND J-KEOGH A TTORNEYS PATENTED mom sum 3 OF 4 PATENTEU APR 20 397i 5 TYL US MOTOR DRIVE SHEET 0F 4 POSITION SENSING UNIT DISC MOTOR 57 DRIVE coumoL u/wr PROGRAM IN N o INPUT VE T R RAYMOND J. KEOGH A T TORNE' Y5 WIRE WOUND DISC ARMATURE This application is a continuation of Ser. No. 620,306, Mar. 3, 1967.

BACKGROUND OF INVENTION in the construction of electric motor armatures it has been generally accepted that the coil span of the individual armature coils must be either slightly greater, or slightly less than the distance between adjacent magnetic pole centers. If the coil span is slightly less, a retrogressive winding results, whereas, if the coil span is slightly greater, a progressive winding results. By having the coil span slightly different from the distance between magnetic pole centers-there is a slight indexing of the winding with each successive armature coil and, as a result, the coils each have the same configuration and are uniformly distributed over the armature surface in a symmetrical fashion.

In conventional DC machines the armature is usually formed with multiturn, preformed coils which are placed in coil slots of a laminated iron core. Since the winding must conform to the armature slot locations, it is desirable to have a uniform indexing of the winding with respect to each successive coil such that all coils have the same shape and all slots contain the same number of conductors.

in recent years the low inertia, printed circuit type of motor has been developed eliminating the iron and coil slots in the armature. The printed circuit motor usually includes a discshaped armature in which radially extending arrays of conductors are usually bonded to opposite sides of an insulating carrier. The conductor patterns for the armature are formed either by chemical techniques, i.e. plating, or etching, or by mechanical stamping techniques. The restrictions upon the winding configurations in a printed circuit motor are even more severe than in the case of a conventional motor. For example, a two-layer printed circuit armature must be formed with single turn coils, the winding must be retrogressive and each coil must index the winding so that all coils have the same configuration.

The printed circuit motor has the advantages of high acceleration and smooth torque, but, because of the single turn coils, can only operate at relatively low voltages.

In a copending application, Ser. No. 511,608 filed Dec. 6, 1965, in the name of Robert Page Burr, having a common assignee with this application, an insulated wire-wound type of motor is illustrated as well as the methods for making the same. This armature can be formed by depositing insulated wire around positioning pins by means of a wire dispensing stylus. Each successive coil, which can be single or multiturn, indexes the winding slightly to obtain a uniformly progressive or retrogressive winding distributed around the positioning pins. This type of armature if constructed with multiturn armature coils can operate at higher voltages but is difficult to construct with automatic machinery because it is necessary to constantly reverse the winding direction while forming the multiturn coils.

BRIEF DESCRIPTION OF THE INVENTION This invention relates to an improved winding technique for wire-wound armatures which do not include slots for the armature coils as well as the apparatus for making the winding.

The armature is formed by depositing insulated wire, preferably around positioning pins, following a pattern forming a plurality of single turn coils which are all in registry and thus, if the pattern is continued, successive armature loops would occupy approximately the same positions. Instead of indexing the winding with the formation of each successive armature coil, the winding is indexed only after a predetermined number of coils have been formed in registry with one another.

BRIEF DESCRIPTION OF THE DRAWINGS An illustrative embodiment of the invention is set forth in the drawings which form part of the specification and wherein:

FIG. 1 is a perspective assembly drawing of the motor;

FIG. 2 is a cross-sectional view of the assembled motor;

FIGS. 3A3D are a series of diagrams illustrating the armature winding sequence;

FIG. 4 is a schematic illustration of winding apparatus for forming the armature.

ARMATURE-CONSTRUCTION GENERALLY The rotating winding for disc-type machine includes a large number of radially extending insulated wire segments distributed to form an annular array which will be adjacent the stationary magnetic pole faces .in the completed machine. These radially extending segments are interconnected to form a continuous winding which is substantially planar, or in other words, is in the form of a relatively thin disc. Successive radially extending segments of the winding are displaced by a distance approximately equal to the distance between pole centers of the associated magnetic structure and are interconnected so that current flowing in the winding will flow in one direction across the south poles and in the opposite direction across the north poles.

The radially extending segments are preferably arranged to minimize the crossing of conductors to thereby minimize the thickness of the armature disc within the magnetic airgap. The thinnest possible winding configuration would occur where all radially extending segments are substantially radial. However, when automatic winding techniques are employed, it is often preferable to have the radially extending segments somewhat skewed.

The portions-of the winding which interconnect the radially extending segments and which lie outside the annular airgap area have a thickness at least twice the diameter of the conductors. As the crossover areas of the armature winding are decreased in width, for example, to reduce the diameter of the annature, additional stacking of the conductors occurs and hence the thickness of the armature winding in these areas increases. However, the crossover connections, by definition, are not within the working airgap of the machine and, therefore, this increased thickness is not detrimental to the performance of the machine.

The winding is formed in a continuous fashion utilizing insulated wire and, since the conductors are insulated, it is possible to cross conductors as desired. The copper distribution can be controlled to achieve a low .copper density in the area of the airgap and a higher copper density in the thicker crossover areas outside the airgap. This control over the relative copper density permits the designer to optimize performance for a particular size armature disc.

An armature turn is the portion of the winding including two successive radially extending segments. When the armature is constructed in accordance with this invention the armature coils are each single turn coils, and, therefore, each armature coil likewise includes two successive radially extending segments. An armature loop is a portion of the winding which spans approximately 360 of the armature. Thus, with an eight-pole machine an armature loop includes four successive armature coils whereas with a l2-pole machine an armature loop includes six successive armature coils.

If the armature coils comprising a loop are in registry, the armature loop spans exactly 360 and if successive armature loops are in registry with the first, the successive armature loops occupy essentially the same positions. For the purposes of this invention, armature coils are defined as being in registry where they are part of an armature loop which, if completed, would be in registry with the prior armature loop or portions thereof. Indexing of the winding occurs when successive armature loops or portions thereof lie in positions adjacent prior armature loops.

FIGS. 3A3D illustrate the step by step formation of an armature winding for an eight-pole machine including 117 annature coils and nine commutator segments. The winding is formed about a jig or die including inner and outer rows of positioning pins, each such row including 27 pins. The inner pins are designated 1a-27a and the outer pins are likewise designated lb27b. The tabs for connection to the commutator segments are designated AL in the order of connection.

Since the armature is for an eight-pole machine, each armature loop includes four armature coils. Since there are 27 positioning pins each armature coil spans approximately eight positioning pins. Since there are H? coils and nine commutator segments, every 13th coil is connected to the commutator.

The armature winding commences by attaching the insulated wire to one of the commutator connection tabs designated as tab A. Tab A is in radial alignment with the first set of positioning pins la and 1b. The winding then passes outside positioning pins 2a, 3b, 4b and 5b in succession. The first armature coil is then completed by passing the wire inside pin 7a.

Next, the second armature coil is formed by passing the wire inside pin 8a, outside pins 10b12b, and inside pin 14a. The winding continues by then forming the third and fourth armature coils by passing inside pin 15a, outside pins 17b- 19b, inside pins 21a and 22a, outside pins 24b26b and inside pin 1a. At this point the first armature loop spanning 360 is completed as is illustrated in FIG. 3A.

The second armature loop is in registry with the first armature loop and is formed following the same sequence around the positioning pins as shown in FIG. 3B. The third armature loop is also in registry as well as the first coil of the fourth armature loop. The winding as it appears after formation of 3% armature loops (13 coils) is shown in FIG. 3C. Each of the 13 coils in the first group are in registry with one another and follow the same pattern about the positioning pins.

A commutator pullout is formed following the first group of 13 coils by passing the winding around tab B. At this point the winding is also indexed so that the second group of 13 coils will lie in positions adjacent the first group.

The winding progresses by passing outside pin 8a, outside pins 9b-11b, inside pins 13a and 14a, outside pins 16b18b, inside pins a and 21a, outside pins 23b-25b and inside pin 27a. The winding as it then appears after completion of four armature loops (l6 coils), including three coils of the second group, is shown in FIG. 3D. Coils 14-16 of the second group are indexed relative to coils 1l3 of the first group.

The winding sequence for the entire 117 coil armature as set forth in Table l.

TAB LE I Start Outer End of of coil pins coil Second pulloutsecond index point TABLE I-Continued Start of coil Outer pins End coil

index point Loop 8.

Loop 9.

Loop 10.

Loop 11.

Loop 12.

Loop 13.

Loop 14.

Loop 15.

Loop 16.

Loop 17.

Loop 18.

index point Loop 19.

Loop 20.

Loop 21.

Loop 22.

Loop 23.

Loop 24.

Loop 25.

Loop 26.

Loop 27.

Loop 28.

Loop 29.

Closing coil.

In designing an armature certain factors must be known at the outset. These factors are, for example:

1 The outside diameter of the armature;

2. The number of pole pairs in the magnetic structure;

3. The flux level which will be produced by the magnetic structure;

4. The desired voltage constant for the armature, that is, the voltage generated by the armature per lOOO r.p.m.;

5. The winding resistance. These factors are interrelated, and, particularly factors 3, 4

wherein Y equals the number of armature turns between commutator connection points, p equals the pairs of poles (also number of armature turns per armature loop), n is an integer multipler and the or sign is chosen to yield a progressive or retrogressive winding, as desired.

Table II indicates the number of conductors required in the armature for an eight-pole machine having various combinations or of commutator segments and distances between commutator connection points in accordance with the relationship:

and 5 must be compatible if a reasonable armature 1s to result. Y=n(p)+l [5] TABLE II 1% loop/ 2% loop/ 3% loop/ 4% loop/ 5% loop/ 6% loop/ pullout pullout pullout pullout pullout pullout No. of (5 (9) 13) (17) (21) (25) commutator conductor conductor conductor conductor conductor conductor segments pairs pairs pairs pairs pairs pairs he 21r wherein k equals volts/rad./sec.; p equals number of pole pairs, gp equals flux per pole in Maxwells, and N equals the number of conductor pairs or armature turns.

Substituting the aforementioned factors into Formula 1 provides the following:

k =0.022 Volt/rad./sec. (3)

Thus, it is determined that approximately 97 conductor pairs (armature turns) provides 0.022 volt/rad./sec. which in turn is equal to approximately 2.2 volts per 1000 r.p.m.

' Formula 1 assumes an armature coil shape which is carefully selected to conform to the shape of the magnets forming the stator poles. In the interest of simplicity and winding speed a simplified configuration has been adopted as shown in FIGS. 3A--3D which is approximately 80 percent efficient. Thus, to obtain the desired characteristics the number of armature turns is increased by a factor of l.2, and hence, approximately 1 16 armature turns are required.

For simplicity the number of commutator segments should be a submultiple of the number of armature turns. If dead coils are to be avoided, the number of commutator segments must be odd if the number of pole pairs is even and vice versa. Furthermore, the commutator connection points should occur at regularly spaced intervals throughout the armature spaced by a number of complete armature loops plus or minus one armature turn, Thus, the coil spacing between commutator connection points can be expressed:

From Table II it can be seen that an armature having 13 commutator segments and commutator connection points spaced by 2% armature loops (nine armature turns or conductor pairs) would have a total of 1 l7 armature turns; an armature with nine commutator segments and a spacing between commutator connection points of 3 /1 loops (l3 conductor pairs or armature turns) would also have a total of l 17 armature turns; and an armature with seven commutator segments and a spacing between commutator connection points of 4 /4 armature loops (l7 conductor pairs or armature turns) would include a total of U9 armature turns. Any of these three combinations could be used for the armature under consideration wherein the desired number of armature turns is approximately 1 16.

A similar table could be developed for an eight-pole machine with the spacing between commutator connection points according to the formula:

- Y=n(p 1 1 In this arrangement the commutator connection points would occur at three-fourth, 1%, 2%, etc., armature loops. From this additional table other combinations can be found which could be used in the design of an armature having approximately 1 16 armature coils.

For the armature shown in FIGS. 3A-3D the combination of nine commutator segments and commutator connection points separated by 3% armature loops (l3 armature turns) has been selected which provides an armature with a total of 117 armature turns, this selection being sufficiently close to the desired number of armature turns.

The criteria for the location of the indexing points is the same as that for the location of commutator connection points, and hence is represented by Formula 4. For convenience, the indexing points are normally selected to coincide with the commutator connection points since it is possible to make both the commutator connection and to index the winding as part of the same step in the winding sequence. However, the commutator connection points and the indexing points need not coincide nor need the coil spacing between commutator connection points be the same as that between successive indexing points.

The number of positioning pins used in forming the armature must be a multiple of both the number of commutator segments and the number of indexing points. In the armature under consideration, the number of commutator segments has been selected as nine and the number of indexing points is also nine. Accordingly, the armature can be constructed using a number of positioning pins which is a multiple of nine. A better winding distribution occurs as the number of positioning pins increases, but as the number of positioning pins increases, but as the number of positioning pins increases, the complexity of. the armature winding apparatus also increases. Furthermore, a practical limit is reached when the spacing between positioning pins of the inner row approaches l pins per inch. For the winding under consideration a multiplier of three has been selected and hence there are 27 positioning pins.

The wire size is determined by measuring the approximate length of an armature turn, multiplying this length by the number of turns in the armature to obtain the total armature length, and by then consultinga wire table to select a wire size which provides the desired armature resistance. From a standard copper wire table number 28 gauge wire is found satisfactory for the armature under consideration having a resistance of 2 ohms end to end.

In many cases it is desirable to construct the armature using multistrand insulated wire as this tends to provide a thinner more evenly distributed winding. Such an armature can be formed by dispensing multistrand wire as the armature is formed. The same armature can also be made by repeating the entire winding sequence several times with a single strand of wire. A pair of 3l-gauge copper wires would provide essentially the same electrical characteristics for the winding under consideration. v

The winding technique in accordance with theinvention is quite flexible and is highly desirable since a large number of different armatures can be made utilizing the same automatic winding apparatus and can often be made using the same winding forms, i.e. winding forms with the same number of positioning pins.

MOTOR ASSEMBLY An insulated wire-wound disc-type motor in accordance with one embodiment of this invention is shown in FIGS. 1 and 2. The motor is enclosed within a two-part housing 1 including a baseplate 2. A stationary permanent magnet structure 3, brush holders 4 and one of the bearings 5 are mounted on the baseplate. The other bearing 6 is mounted within a central opening in the cup-shaped member 7 forming the other part of the motor housing, member 7 being secured to the baseplate at its periphery by means of screws 8.

The motor shaft 9 is journaled in bearings 5 and 6, and includes an intermediate section 10 of increased diameter. The increased diameter section is positioned between the bearings and prevents axial movement of the shaft. The motor armature 14 is mounted on shaft 9 by means of a flanged hub 11 rigidly secured to the shaft and an associated flanged nut 12 which cooperates with the external threads on the shank portion of the hub. The dielectric disc 17 forming part of armature 14 is rigidly secured between the flanges of nut 12 and hub 11.

The armature winding constructed as described in relation to FIGS. 3A3D is supported on a dielectric disc 17 shown adjacent the winding for illustration purposes. The commutator segments 16 are centrally located with respect to the winding and are secured to dielectric disc 17. The flange of hub 11 provides structural backing for the commutator to prevent distortion of the armature disc due to the force exerted against the commutator by the brushes.

The motor illustrated in FIGS. 1 and 2 is an eight-pole motor and therefore the permanent magnet structure 3 is divided into eight segments which provide the necessary pole faces. The permanent magnet structure is a unitary ringshaped member provided with slots which define individual bosses that form an annular array of the pole faces lying in a plane perpendicular to the axis of rotation. The magnetic structure is a cast or sintered unit fashioned from a nickelaIuminum-cobalt alloy such as Alnico. The structure is magnetized to provide pole faces of alternating magnetic polarities. A ring 18 of soft iron is secured to the rear of the housing by screws 19 to complete the magnetic path between adjacent pole faces. The space between ring 18 and the pole face surfaces is the working airgap of the machine and must be sufficient to accommodate the armature and provide a working clearance.

A few turns of heavy, insulated wire, referred to as a charging winding, are placed around the individual pole pieces prior to final assembly. Charging winding 39 passes outside one pole piece 22, through a slot 20, and then inside the next pole piece 21, etc., twice around the unit. This winding in effect surrounds one pole piece in a clockwise direction, and surrounds the adjacent pole piece in the counterclockwise direction and, therefore, current flow through the charging winding tends to produce poles of alternating magnetic polarity. After final assembly the charging winding is energized to magnetize the permanent magnets.

The radially extending segments of the armature winding lie within the working airgap adjacent the pole faces. The thickness of this portion of the armature winding within the airgap is maintained at a minimum. The thicker portions of the winding which include the crossover connections are located outside the airgap.

Brush holders 4 each include an insulated sleeve having a cylindrical body portion 25, the end of which extends through suitable openings 27. The brushes 29 are rectangular in cross section and extend from the brush holders through suitably dimensioned rectangular openings 28. The end of the brush holder opposite the rectangular opening is internally threaded and adapted to receive a flat head screw 32. When the screw is inserted, pressure is applied to the brush via a spring 30 and small pressure plate 31, so that the brush is maintained in engagement with commutator segments 16. The number of brushes and the placement relative to the pole faces varies in accordance with the armature winding and current carrying requirements.

WINDING APPARATUS The armature can be constructed by distributing insulated wire upon a planar surface in continuous fashion. This is accomplished using a winding form 40 as shown in FIG. 4 having appropriately positioned pins 41 extending upwardly from the planar surface so that the insulated wires forming the armature can be wound around the pins. The pins are located in two concentric rows. The positioning pins in the inner row are designated 1a27a, and the positioning pins in the outer row are designated 1b--27b, thereby corresponding to those shown in FIGS. 3A-3D.

The insulated wire can be distributed directly upon the planar surface of the winding form, or upon a disc blank 44 as shown. Holes are drilled or punched into the disc blank corresponding to the positions of the positioning pins and, hence, when the blank is dropped into position as shown in FIG. 4, the pins extend upwardly through the blank. The disc blank includes the commutator segments 45 secured to the disc surrounding a central opening which will accommodate the motor shaft and hub structure. Each commutator segment includes an upwardly extending tab, these tabs being used to position the commutator pullout loops of the winding.

Winding form 40 is coupled to a motor 50 which rotates the winding form in the clockwise direction. A position sensing unit 51 is coupled to the motor shaft and provides electrical signals indicating the instantaneous position of the winding form.

The insulated wire is dispersed by a stylus 52 mechanically coupled to a lead screw 53 which moves the stylus radially relative to the winding form. The movement of the stylus is controlled by a bidirectional, variable speed motor 54 coupled to the lead screw.

The operation of motors 50 and 54 is controlled from a control unit 56, respectively, via a disc motor drive 57 and a stylus motor drive 58. The control unit operates in accordance with a preselected program to coordinate the movements of .the winding form and the stylus to form the desired winding configuration. The entire armature winding is formed while the winding form rotates in a single direction, and hence, since it is not necessary 'to periodically reverse the direction, relatively high winding speeds are readily attainable. As the winding form rotates, position sensing unit 51 provides signals indicating the position of the winding form, and these signals are compared with the program to control the corresponding radial movements of the stylus.

The winding forms and control programs are preferably interchangeable so that the same winding apparatus can form armatures of various sizes and various configurations.

After the insulated wire has been distributed to form the.

winding it is necessary to give it structural integrity so that the winding can be mounted on the motor shaft. There is no significant tendency for the magnetic field to deflect the armature winding in an axial direction and therefore the armature need only have sufficient rigidity to maintain clearance with respect to the stationary structure and to transmit torque between the winding and the motor shaft. Structural integrity is achieved by one of the following processes or combinations thereof:

1. The winding is formed upon the surface of a thermoplastic disc blank as shown in FIG. 4, and when completed, heat and pressure are applied to press the winding into the disc blank. The winding, particularly in the annular airgap area, is embedded in the disc and has a thickness no greater than the insulated wire. The same result can be achieved by forming the winding without the disc blank and thereafter pressing the thermoplastic disc down upon the preformed winding.

2. The winding can be laminated between a pair of thermoplastic discs. The winding is preformed and thereafter placed between the laminating discs, or can be wound upon one of the 'disc blanks as shown in FIG. 4. Preferably, the structure is compressed in the airgap area to minimize the thickness.

3. The winding can be formed directly upon the winding form without a disc blank and thereafter coated, as by spraying, dipping or the like, with a suitable dielectric medium to provide structural integrity.

4. The winding can be formed directly upon the winding form without a disc blank and thereafter spotted with an adhesive material to bond the insulated wires at points where the conductors cross.

5. The winding can be fonned with a heavy gauge wire which by itself possesses sufficient structural integrity.

SPECIFIC ARMATURE DESIGNS There are a substantial number of possible armature designs within the scope of the invention. Several specific examples, in addition to that previously described, are as follows:

EXAMPLE NO. l

The positions of the commutator pullouts need not coincide with the positions of the index points. A winding sequence for such an armature could be:

start at a commutator connection;

wind one full armature loop;

index ahead two pins;

wind 1% armature loops;

form a commutator pullout;

repeat.

The parameters and predicted operating characteristics for such an armature are as follow:

Number of Poles 8 poles Number of Commutator Segments 27 segments Number of Annature Conductors 594 conductors Number of Armature Turns 297 turns Number of Positioning Pins per row 81 pins Number of Armature Turns Between Indexing Points 1 1 turns Number of Armature Turns Between Commutator Pullouts 11 turns EXAMPLE NO. 2

The indexing points can be separated by less than a complete armature loop as indicated, for example, by formula 1.9 ohms 5.5 v/kpm 7.4 in.-oz./amp

0.18 in.-oz./kpm

6 when n equals one. For a machine including four pole pairs the armature winding sequence would be:

start at a commutator connection;

wind three-fourths of an armature loop;

index backward (retrogressive);

form a commutator pullout;

repeat. v I The parameters and predicted operating characteristics for such an armature are as follows:

Number of Poles 8 poles Number of Commutator Segments 35' segments Number of Conductors 210- conductors Number of Turns turns Number of Pins in Form (Outer Row). 105 pins Number ofTurns Between Indexing Points 3 turns Number of Turns Between Commutator Segments 3 turns Type of Winding Retrogressive Wire Size 024 A.W.G.

' Outside Diameter of Armature 6.6 inches Inside Diameter of Armature 3.5 inches Armature Resistance (Excluding Brushes) Field Flux 3.8 kilogauss Voltage Constant, K, 5.5 v./kpm Torque Constant, K, 7.4 in.-oz./amp Damping Constant, 1.21 in.-oz./kpm

EXAMPLE NO. 3

0.3 ohms Number of Poles 8 poles Number of Commutator Segments 15 segments Number of Conductors conductors Number of Turns 75 turns Number of Pins in Form (outer row) 45 pins Number of Turns Between Indexing Points 10 turns Number of Turns Between Commutator Segments turns Type of Winding Retrogressive Wire Size Double Strand (Bifilar) 028 A.W.G.

Outside Diameter of Armature 3.6 inches Inside Diameter of Armature 2.0 inches Armature Resistance (Excluding Brushes) Field Flux 5.5 kilogauss Voltage Constant, K, 1.4 v./kpm

Torque Constant, K, 1.89 in.-oz./amp

Damping Constant, K 0.176 in.-oz./kpm

0.25 ohms EXAMPLE NO. 4

An armature having characteristics almost identical to Example No. 3 can be formed using an even number of positioning pins. The winding sequence for such an armature being progressive and having coincident commutator pullouts and indexing points could be:

start at a commutator connection;

wind 1% armature loops;

form a commutator pullout;

repeat. The parameters and predicted operating characteristics are as follows:

Number of Poles 8 poles Number of Commutator Segments l 1 segments Number of Conductors 154 conductors Number of Turns 77 turns Number of Pins in Form (Outer Row) 44 pins Number of Turns Between Indexing Points 7 turns Number of Turns Between Commutator Segments 7 turns Type of Winding Progressive Wire Size Double Strand (Bifilar) 028 A.W.G.

Outside Diameter of Armature 3.6 inches lnside Diameter of Armature 2.0 inches Armature Resistance (Excluding Brushes) Field Flux 5.5 kilogauss Voltage Constant, K l .44 v./kpm

Torque Constant, K, 1.94 in.-oz./amp

Damping Constant, K 0.181 in.-oz./kpm

I EXAMPLE NO.

The indexing points can be separated by more than a plurality of armature loops. The winding sequence for an armature having indexing points separated by 3% armature loops could be:

Start at a commutator connection;

Wind 3% armature loops;

Form a commutator pullout;

lndex backward one positioning pin;

Repeat.

The parameters and predicted operating characteristics for such an armature are as follows:

Number of Poles 8 poles Number of Commutator Segments 17 segments Number of Conductors 442 conductors Number of Turns 221 turns Number of Pins in Form (Outer Row) 68 pins Number of Turns Between Indexing Points 13 turns Number of Turns Between Commutator Segments turns Type of Winding Retrogressive Wire Size Double Strand (Bifilar) Outside Diameter of Armature 3.6 inches Inside Diameter of Armature 2.0 inches Armature Resistance (Excluding Brushes) 0.74 ohms Field Flux 5.5 kilogauss Voltage Constant, K 4.14 vJkpm Torque Constant, K, 5.60 in.-oz./amp

Damping Constant, K D 0.52 in.-oz./kpm

EXAMPLE NO. 6

The distance between commutator connection points can be different from the distance between indexing points. A winding sequence for such an armature could be:

start at a commutator connection;

wind 2% armature loops;

index ahead one positioning pin;

wind one armature loop;

form commutator pullout;

winding 1% armature loops (total of 4% loops from beginning);

index ahead one positioning pin;

0.255 ohms 02 s A.W.G.

wind two armature loops; form commutator pullout; continue sequence, indexing after every 2% armature loops, and forming a commutator pullout after every 3% armature loops. The parameters and predicted operating characteristics for such an armature are as follows:

Number of poles 8 poles Number of Commutator Segments 9 segments Number of Armature Conductors 234 conductors Number of Armature Turns 1 17 turns Number of Positioning Pins Per Row 27 pins Number of Armature Turns Between Indexing Points 9 turns Number of Armature Turns Between Commutator connection Points 13 turns Type of Winding Retrogressive Wire Size 28 A.W.G. Outside Diameter of Armature 3 .6 inches Inside Diameter of Armature 2 inches Armature Resistance (including brushes) 0.5 ohms Field Flux 5.3 kilogauss Voltage Constant K 2.2 v./kpm Torque Constant K, 2.9 in.-oz./amp Dumping Constant K 1 in./kpm While several specific embodiments have been described in detail it should be obvious that there are numerous other embodiments within the scope of the invention. The invention is applicable to cylindrical armatures as well as disc shaped armatures, and is more particularly defined in the appended claims.

I claim: 1. An armature for an electrical machine having a multipole magnetic structure comprising a closed winding including a plurality of single turn armature coils interconnected in a wave configuration, each armature coil including a pair of winding segments spaced approximately in accordance with the distances between adjacent pole centers of the associate magnetic structure, each single pair of winding segments being interconnected at at least one of its ends to one end of a pair of winding segments on said armature spaced from said each single pair of winding segment a distance substantially equal to the distance to the pole centers of the next adjacent pair of poles of said multipole magnetic structure, the armature coils being divided into a plurality of similar groups, each of said groups including n(p)ial coils, where n is an integer and p is the number of pole pairs in the magnetic structure,

each similar group of said plurality of similar groups being indexed relative to the other of said plurality of similar groups making up such armature so that said groups are uniformly spaced and distributed on said armature.

2. An armature according to claim 1 wherein said winding is secured to a disc-shaped, dielectric carrier.

3. An armature according to claim 1 wherein said winding is laminated into a dielectric disc carrier.

4. An armature according to claim 1 wherein said winding is formed with insulated wire and said wire is physically bonded at intersections where they occur throughout the winding.

5. An armature according to claim 1 including a commutator having a plurality of commutator bars, said winding being connected to individual ones of said commutator bars at regularly spaced intervals throughout said winding.

6. An armature according to claim 5 wherein the number of coils in each of said groups is n(p)ial and the number of coils between commutator connection points is n'(p)il', n and n' being integers and p being the number of pole pairs in the magnetic structure.

7. An armature according to claim 5 wherein said commutator connection points coincide with the indexing points between successive groups of coils.

8. An electrical machine comprising a stator including means for providing an array of pole faces of alternating magnetic polarity,

an armature having an insulated wire winding including a plurality of single turn armature coils interconnected in a wave configuration,

each armature coil including a pair of winding segments spaced approximately in accordance with the distance between adjacent pole centers of said stator, each single pair of winding segments being interconnected at at least one of its end to one end of a pair of winding segments on said armature spaced from said 'each single pair of winding segment a. distance substantially equal to the distance to the pole centers of the next adjacent pair of poles of said multipole magnetic structure,

said armature coils being divided into a plurality of similar groups, the number of armature coils in each said group is n(p)l, where n is an integer and p is the number of pole pairs in said stator,

each similar group of said plurality of similar groups being indexed relative to the other of said plurality of similar groups making up such armature so that said groups are uniformly spaced and distributed on said armature,

a commutator including a plurality of commutator bars, said winding being connected to individual ones of said commutator bars at regularly spaced intervals throughout said winding, and

means for energizing said winding via said commutator.

9. An electrical machine according to claim 8 wherein the number of armature coils between successive connections to said commutator bars is n'(p)- Ll where n'(p)il where n is an integer and p is the number of pole pairs in said stator.

10. An electrical machine according to claim 8 wherein the connections to said commutator bars coincide with the indexing points between successive groups of armature coils.

@33 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,525,624 Dated April 20, 1971 Raymond J. Keogh Inventofla) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Claim 6, column 12, line 68,

"is n(p)'lal" should read is n(p)'l'1 In Claim 8, column 13, line 17,

"n(p)1," should read n(p)fl,

Signed and sealed this 11th day of April 1972.

(SEAL) Attest:

ROBERT GOTTSCHALK EDWARD M.FLETCHER,JR.

Commissioner of Patent Attesting Officer 

1. An armature for an electrical machine having a multipole magnetic structure comprising a closed winding including a plurality of single turn armature coils interconnected in a wave configuration, each armature coil including a pair of winding segments spaced approximately in accordance with the distances between adjacent pole centers of the associate magnetic structure, each single pair of winding segments being interconnected at at least one of its ends to one end of a pair of winding segments on said armature spaced from said each single pair of winding segment a distance substantially equal to the distance to the pole centers of the next adjacent pair of poles of said multipole magnetic structure, the armature coils being divided into a plurality of similar groups, each of said groups including n(p) + OR - 1 coils, where n is an integer and p is the number of pole pairs in the magnetic structure, each similar group of said plurality of similar groups being indexed relative to the other of said plurality of similar groups making up such armature so that said groups are uniformly spaced and distributed on said armature.
 2. An armature according to claim 1 wherein said winding is secured to a disc-shaped, dielectric carrier.
 3. An armature according to claim 1 wherein said winding is laminated into a dielectric disc carrier.
 4. An armature according to claim 1 wherein said winding is formed with insulated wire and said wire is physically bonded at intersections where they occur throughout the winding.
 5. An armature according to claim 1 including a commutator having a pluraliTy of commutator bars, said winding being connected to individual ones of said commutator bars at regularly spaced intervals throughout said winding.
 6. An armature according to claim 5 wherein the number of coils in each of said groups is n(p) + or - 1 and the number of coils between commutator connection points is n''(p) + or - 1; n and n'' being integers and p being the number of pole pairs in the magnetic structure.
 7. An armature according to claim 5 wherein said commutator connection points coincide with the indexing points between successive groups of coils.
 8. An electrical machine comprising a stator including means for providing an array of pole faces of alternating magnetic polarity, an armature having an insulated wire winding including a plurality of single turn armature coils interconnected in a wave configuration, each armature coil including a pair of winding segments spaced approximately in accordance with the distance between adjacent pole centers of said stator, each single pair of winding segments being interconnected at at least one of its end to one end of a pair of winding segments on said armature spaced from said each single pair of winding segment a distance substantially equal to the distance to the pole centers of the next adjacent pair of poles of said multipole magnetic structure, said armature coils being divided into a plurality of similar groups, the number of armature coils in each said group is n(p) + or - 1, where n is an integer and p is the number of pole pairs in said stator, each similar group of said plurality of similar groups being indexed relative to the other of said plurality of similar groups making up such armature so that said groups are uniformly spaced and distributed on said armature, a commutator including a plurality of commutator bars, said winding being connected to individual ones of said commutator bars at regularly spaced intervals throughout said winding, and means for energizing said winding via said commutator.
 9. An electrical machine according to claim 8 wherein the number of armature coils between successive connections to said commutator bars is n''(p) + or - 1, where n''(p) + or - 1, where n'' is an integer and p is the number of pole pairs in said stator.
 10. An electrical machine according to claim 8 wherein the connections to said commutator bars coincide with the indexing points between successive groups of armature coils. 